Generally speaking, lighting is designed to adequately light a target area from some distance. However, there are some lighting applications which particularly focus on precise definitions of “adequately” and light target areas which are complex (e.g., in shape, in spatial orientation) from long distances (vertical and/or horizontal). These more precise lighting applications sports lighting applications being an example are in a separate class of lighting design, and one which benefits from improved beam control.
Focusing on such precise lighting applications, there are a number of issues in the art. For example, if the target is complex because of sheer size, then regardless of complexities due to shape or dimension (e.g., if uplight is needed) a primary concern is making a luminaire (also referred to as a lighting fixture) as luminously dense as possible—packing light sources as tightly as possible, using materials with the fewest inefficiencies or losses, tailoring operating conditions, etc.—so to ensure a maximum output and, therefore, minimize the number of needed fixtures. Of course, a luminously dense lighting fixture is not in and of itself entirely adequate for such lighting applications; a large quantity of light is not a benefit if it is not controlled in a precise manner. As such, another primary concern is how to use a number of light directing (e.g., lenses) and light redirecting (e.g., reflectors) devices so to ensure that said large quantity of light is shaped and directed in a preferred manner—for example, shaped so not to spill past a field of play while aimed so to be overlapped with other quantities of light so to build up a composite beam of desired intensity. Of course, this also introduces concerns. The composite beam from that luminously dense lighting fixture can only be shaped, directed, cut off, and otherwise controlled to a certain point using conventional wisdom and devices before the center beam starts to perceivably shift; the center beam typically being the point of maximum candela, but also often the photometric center of the composite beam. To be clear—any situation with an external visor will cause some minor shifting of the center beam projected from the emitting face of a lighting fixture including said visor; this is simply the nature of light redirection. This is the primary reason why center beam shift is discussed herein in the context of perceivable shift—which can be thought of thusly. A beam pattern has a defined shape and distribution. The maximum candela is a point somewhere in the defined shape, distribution tapering off therefrom. Shifting of the maximum candela from point A in the shape to point B in the shape is relatively unimportant as long as the distribution and shape are preserved. When maximum candela (or photometric center) is shifted so much (e.g., due to excessive pivoting of a visor) that shape and/or distribution is perceivably impacted, issues arise; in this sense, such shifting of the center beam is a bellwether for poor lighting design. Perceivable shifting of the center beam is a large concern in precision lighting design because, as is well known in the art, computer programs have long been used to optimize virtual lighting designs which form the blueprint for actual lighting systems, and often rely on the center beam as the aiming point for the virtual lighting fixtures which are placed and optimized. If the virtual center beam and the actual center beam do not match up when the actual product is installed and aimed, then beam patterns will not overlap as intended (resulting in, e.g., dark spots) and distribution will be off (resulting in, e.g., violation of lighting uniformity requirements in the specification); and generally speaking, beam control will not be maintained. These are but a few known concerns relating to beam control in the art of precision lighting design.
Currently a piecemeal approach is often taken to provide some degree of beam control in precision lighting design: higher efficacy light sources might be paired with a relatively inefficient luminaire housing, a visor might be added after the fact due to perceived glare but doing so results in a decrease in overall light levels, so then the light sources might be driven harder to compensate thereby reducing what was previously a high efficacy, and the compensation cycle continues. Each lighting fixture is typically designed in isolation with little to no attention paid to how that lighting fixture will “live” on a mount on a pole—how it will interact with other lighting fixtures on a common crossarm or other structure when trying to blend or overlap the composite beam output with that of other lighting fixtures. What is needed is a more synergistic approach to beam control which takes into account all of the aforementioned concerns.
Thus, there is room for improvement in the art.